a Very common task in Creo is remodeling. either it is a model you've downloaded from vendor website either new/old design created in other cad package.
when creating the model it's very common to use references, in sketch, from "orig" model, using "project" option, then delete those references, from sketch references, in order to have a fully define/dimensioned sketch.
in order to accelerate the modeling process it would be very useful to have similar ability in extrude/revolve/etc.
so you'll be able to use "To reference" depth option as the desire depth, select the desired ref, and then switching to "variable" in order to get the current value of depth.
This would be significant time saver as today you're force to measure the depth before and type it manually.